Casilla is a prototypical hard-throwing fastball-slider reliever with command issues. You've probably seen many pitchers like him before, and Casilla won't be the last of his ilk either.

He's been the hardest thrower on the A's this year, with an average fastball velocity of 94.3 mph.

However, the pitch has been crushed all season long, coming in at 2.04 runs below average per 100 pitches. That's bad news for a pitcher who throws the heater 65 percent of the time.

Casilla has always earned plaudits from scouts for his slider, which he throws 29 percent of the time. It has fared much better than the fastball this year, coming in at .98 runs above average per 100 pitches.

However, since Casilla, like most pitchers, turns to the fastball far more than the breaking ball, the high quality of the slider ultimately does little to offset the awful results of the fastball.

While the fastball and slider have always earned praise in scouting reports, Casilla's changeup has never been considered any good. Scouts say he throws it too hard and doesn't have good arm action on the pitch.

Casilla barely uses it, throwing it about once every 13 pitches.

Yet, in a season where so much has gone wrong for the Dominican righty, his supposedly awful changeup has shined, coming in at 3.24 runs above average per 100 pitches.

In my last article, I analyzed the incredible success of Tim Lincecum's changeup and hypothesized that part of its success was that hitters were too busy looking for his fastball and curve, and the changeup catches them by surprise.

It's certainly possible that Casilla's changeup has succeeded in the same fashion. When the scouting reports say the changeup is bad, and he only throws it once or twice an inning, there's no real reason for a hitter to worry about the pitch.

However, whatever the reason, Casilla's changeup has succeeded this year, and his slider has been good as well.

Unlike Lincecum, whose performance is so incredible that it would be a terrible idea to mess with him, Casilla needs to make a big adjustment to transform himself back into a decent reliever.

Therefore, the A's coaching staff should tell Casilla (and the catchers, since they call the pitches), that they want him throwing more sliders and changeups.

Perhaps instead of throwing 64.6 percent fastballs, 28.7 percent sliders, and 6.7 percent change-ups, Casilla could switch to a 50-30-20 pitch allocation and see what happens.

In a worst-case scenario, the changeup gets exposed and hammered with the increased usage. In a best-case scenario, he becomes a hard-throwing three-pitch setup man.

The A's should take the risk and alter Casilla's pitch selection, because the current incarnation of Casilla certainly isn't getting it done. Whether a pitcher has a 6.00 ERA or an 8.00 ERA really doesn't matter: Neither figure are Major-League worthy.

Casilla's change-up seems to be the best thing he has going for him right now. The A's should exploit that and find out if it's for real.